Equalizing system



P. C. COLLINS EQUALIZING SYSTEM Filed Dec. 18, 1941 May 21, 1946.

2 Sheet-Sheet 1 mm mm km in v QM as Q Nv ow nm INVENTOR PAUL C- COLLINS May 21, 1946. P. c. coLLiNs EQUALIZING SYSTEM Filed Dec. 18, 1941 2 Sheets-Sheet 2 INVENTOR PAUL C. C0..L|N$

Patented May 21, 1946 UNITED STATE 2,400,685 EQUALIZING SYSTEM Paul C.

Collins, Norwood, Pa., asslgnor to The Baldwin Locomotive Works, a corporation of Pennsylvania Application December 18, 1941, Serial No. 423,447 I (01. 6097) 4 Claims.

This invention relates generally to an apparatus and system for controlling two independently actuated power elements particularly hydraulically actuated rams and cylinders of hydraulic presses.

While my present invention is applicable to various fields employing two independently hydraulically actuated rams and cylinders, yet it is particularly applicable in the field of hydraulic presses, especially of the type for bending plates which usually requires a bending beam of considerable length and which is actuated by two sets of rams and cylinders, one set at each end of the .beam. In addition to bending plates with a cylindrical shape for use in boilers, pipe line conduits, etc., it is frequently necessary to bend them conically or with varying curvature requiring the plate to be bent to a greater extent at one end than at the other end. This requires the beam to be adjustable to various angles to produce different shapes and such variations may occur from plate to plate or within the same plate. The necessity for such a flexible operating condition is coupled with the more rigid operating condition that after any one of the angular adjustments has been made it is necessary to vertically move the entire beam uniformly preferably during both up and down movement. The massiveness of hydraulic press equipment of this type and the use of a plurality of independent sources of power adds to the difficulties in overcoming the above problems.

One object of my invention is to provide an improved apparatus and control system for coordinating the movement of two independently movable power elements. Another object of my invention is to provide an improved control apparatus for insuring identical movement of two independently hydraulically actuated elements whereby any momentary tendency toward unequal movement will be immediately corrected without interrupting the power supply to the entire system.

A further object is to provide an improved control apparatus for establishing any desired initial unbalance or angularity of the bending beam and thereafter maintaining the same in said condition while uniformly bodily moving the same.

Another object is to provide improved apparatus for accomplishing the foregoing objects in a relatively simple and inexpensive manner that has a high degree of sensitivity, accuracy and responsiveness combined with positive operation but without conflict between the various adjustments.

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawings in which:

Fig. 1 is a transverse section through a press embodying my improved control system;

Fig. 2 is a vertical section taken substantially on the line 2--2 of Fig. 1;

Fig. 3 is a horizontal section taken substantially on the line 3-3 of Figs. 1 and 2;

Fig. 4 is a section taken substantiallyon the line 44 of Fig. 3;

Fig. 5 is a diagrammatic perspective of my improved control system; and

Fig. 6 is an enlarged sectional view taken substantially on the line 6-6 of Fig. 5.

In the specific illustration of my invention herein, I have shown diagrammatically a plate bending press having a base I and an upper crosshead 2 supported upon the base I by usual joining columns 3. A bending beam 4 usually of considerable length is suitably supported in a pair of end platens 5 and 6, the bending beam preferably being disposed, as shown in Fig. 5, within slots I and 8 formed in said platens respectively. The platens 5 and 6 are respectively provided with sets of independently movable.

power operated elements, specifically power motors such as hydraulically operated rams 9 and I0 and cylinders II and I2. Each set is specifically shown in Fig. 2 as comprising two rams and cylinders, although more or less of the same may be employed depending upon the size or capacity of the press. The sets of cylinders I I and I2 are suitably supported upon the upper press head 2. Pullback rams and cylinders I4 and I5 are supported on the crosshead 2 whose rams are connected-by links I6 and H to the beam 4, Fig. 1. To bend a plate, it is supported upon usual dies or blocks on base I whereupon bending beam 4 is moved down under the power of fluid pressure supplied to the main cylinders I I and I2.

To insure identical bodily vertical movement of beam 4 whose length may be of considerable magnitude, I have provided my improved control system which as diagrammatically illustrated in- Fig. 5, comprises a pair of racks l9 and 20 connected respectively to the end platens 5 and 6. Rack I9, in turn, operates a pinion 2I for rotating a shaft 22 suitably journalled on the upper stationary crosshead 2. of gears 23 and 24, the latter being connected This shaftdrives a pair to shaft 25, Fig. 3, of a differential mechanism generally indicated at 26. Similarly, rack 28 drives a pinion 21, shaft 28, gear 29 and gear 38 to rotate a second shaft 3|, Fig. 3, of differential 26, it being noted, however, that gears 23 and 29 are on opposite sides of the gears 24 and 38 thereby rotating shafts 25 and 8|, Fig. 3, in opposite directions. Bevel gears 32 and 33 are secured to shafts 25 and 3| and these are connected together byv a series of differential pinions 34 mounted for rotation about a suitable shaft 35 supported in a suitable casing 36. End plates 31 and 38 are secured to casing 36 and are provided with hollow trunnions 39 and 48 journalled in a pair of bearings 4| and 42. These bearings are supported on top of crosshead 2. So long as the platens 5 and 6 move vertically at an identical rate their respective racks I9 and 28 will cause differential shafts 25 and 3| to rotate at the same rate. but in opposite directions thereby causing difierential pinion 34 to rotateabout the' axis of shaft 35 but without causing any rotation of the diflerential casing 36. However, if one of the platens momentarily moves faster than the other platen or vice versa, then a difierential movement will occur between I the bevel gears 32 and 33 and accordingly cause differential pinions 34 to rotate casing 36 about the axis of shafts 25 and 3|. I employ this differential action in combination. with fluid supply means specifically in the form of two fluidpumps 44 and 45, Fig. 5, preferably of the well-known variable positive displacement Hele-Shaw type having usual radial pistons and adapted to be reversed to eifect a pullback operation. These pumps are diagrammatically indicated as being connected by lines 41 and 46 to the main cylinders II and I2- and bein connected by lines 49 and 58 to the pullback cylinders I4 and I5. The pullback cylinders are shown in Fig. 5 for diagrammatic purposes as being at the lower end of the main cylinders.

The end platens 5 and 6 will move upwardly at a uniform rate so long as the pumps discharge equal volumes of fluid but in the event of leakage or, other adverse conditions either one of the platens should move faster than the other, then it is necessary to adjust one or the other of the pumps. To eifect this adjustment, I employ the difi'erential action previously described by mounting, Fig. 3, an eccentric 5| upon th hollow shaft 48 so that the eccentric angularl moves in response to and to the extent of movement of difjournalled in brackets 16. The arm 15 is connected by a link 11 to a second power medium control mechanism also specifically shown as a pump stroke adjusting lever 18 which has a fixed pivot at its upper end. The upper end of lever 12 is connected by a link generally indicated at 88 to an arm 8| while the lower end of lever 64 is connected by a link generally indicated at 82 to an arm 83. Arlns 8| and 83 are rigidly connected to a shaft 84 which may be angularly adjusted by a pair of bevel gears 85 and a manual control lever 86. As will be seen later, the ele- ,ments 54-59 and I88-I82 are the beam angle adjusting mechanism.

Each of the links 88 and 82 haveyieldable connections both numbered 81 as they are identical in construction. This connection, as shown in Fig. 6, comprises a spring 89 interposed between two plates 98 slidably mounted on a rod 9| 20 and adapted to be selectively moved by nuts 92 and 93 on rod 9|.

v the link 88 or 82, while acasing 94 enclosing the spring 89 and forming stop flanges for washers'98 forms the remaining portion of said links. These yieldable connections are-sufllcientlv rigid to allow shifting of the manual control lever 86 to' either its forward position 96 or to its reverse position 91 without any lost motion due to the presence of the spring. The purpose of these spring connections .is explained later.

Operation- 1f it is assumed that the platens 5 and 6 are adjusted to their desired relative vertical relation, then lever 86, Fig. 5, is shifted to the shaft 84 in a counterclockw right and laterally to position 96 thereby rotating e direction through gears 85. Arm 8| thereupon swings lever 12 and pump control lever 18 in counterclockwise directions to adjust pump 44 to its forward position for discharging fluid to the main cylinder I I. Also arm 83 causes lever 64 and pump lever 18 to shift pump 45 to its forward position for supplying fluid to main cylinder l2. Fluid from the pullback cylinders I5 may be drawn through their respective pipes 49 and 58 to the suction side of" 5 the pumps.

So long as the end platens 5 and 6 move downwardly at the same rate. which is equivalent to saying that the rams 9 and I8 maintain their same relative axial positions, the racks I9 and 28 will equally rotate the pinions' 2| and 0, 21 in opposite directions thereby rotating diiferferential casing 36. An eccentric sleeve 52 is con- 51 upon which a pair of rigidly interconnected arms 58 and 59 are journalled, the arm 58 being. connected by a rod 68 to a second set of levers. This second set of levers 6| is journalled for rotation about a fixed axis supported in brackets 62. The lower end of the second set of levers has a shaft 63 upon which is freely journalled lever 64 whose upper end is connected by a rod 65 to a lever 66 and 61 journalled about a fixed axis in brackets 68. The arm 61 is connected by a link 69 to a. power medium control mechanism, specifically shown asa pump stroke adjusting lever 18 having a fixed pivotal support at its upper end. A second lever 12 is freely journalled on shaft 63, the lower end of saidlever being connected by a link 13 to a pair of arms 14 and 15 pivotally supported at their upper ends about a fixed axis rection about its pivotal shaft 55 and accordingly ential shafts 25 and 3|, Fig. 3, in equal and opposite directions with the result that differential casing 36 will remain stationary. However, if platen 5 should momentarily move down faster 'than platen 6 so that the predetermined relative axial positions of the ramsis not maintained, then the differential gear 32 will no longer maintain an equal and opposite rotation with gear 33. The differential pinion 34 will cause a slight an-. gular adjustment of the diil'erential casing thereby to angularly adjust eccentric 5|. This will shift link 53, Fig. 5, to the right thereby swinging the first set of levers 54 in a counterclockwise di- 5 shift link 68 to the right inasmuch as am 59 is held at its lower endby a link I88, arm I 8| and worm and gear I82. The arms 59 and 58 to which link 68 is connected are 'journalled on shaft 51. Movement of link 68 to the right causes the sec- 7 0nd set of levers '6I to swing in a counterclockwise direction about its upper'end and accordingly cause link to be moved to the right inasmuch asthe lower end of arm 64 is held against any substantial movement by link 82 and its connection'to the rigidly positioned manual lever 86.

The rod 9| forms one part of 7 It! in a clockwise direction thereby rotating arm Movement of link 85 to the right rotates arms 88 and 61 in a clockwise direction thereby moving the lower end of pump lever 18 to the left. Conversely, the upper end of lever 12 is held against any substantial movement by its connection through link 80 to manual lever 88 and consequently the lower end of lever 12 is swung to the right by counterclockwise movement of the sec ond set of levers thereby to move the lower end of pump lever 18 to the right. Thus it is seen that the two pumps are adjusted oppositely in the event that the end platens and a do not move uniformly. The more the platens move out of synchronism with each other the more the pumps are oppositely adjusted thereby to increase the rate of discharge to the retarded main ram and decreasing the supply of fluid to the other ram until they again move identically whereupon the above linkage connections operate reversely to bring the pumps into equal discharge. It is, of course, to be understood that the two sets of main cylinders are of the same diameter, although if for any reason the cylinders should be of different diameters or if more leakage should occur in one cylinder or the other, my improved control system will still function to bring the two end plates into identical movement.

To raise the platens lever 85 is shifted to the left, Fig. 5, and thence laterally into notch 91 whereupon the linkages are shifted in the opposite direction to that above described and accordingly completely reverse the two pumps 44 and 45, thereby to supply fluid to the pullback cylinders l5. During reverse operation, the pumps will be momentarily adjusted in the event that platens 5 and 6 do not rise at the same rate.

To angularly adjust the bending beam 4 and maintain it in that position during up and down movement, the operator adjusts worm gears i02, Fig. 5, thereby rotating arm IOI in one direction or the other depending upon whether platen 5 or 5 is to be elevated above the other platen. Adjustment of arm IM, say in a counterclockwise direction, causes arms 58 and 59 on the first frame 54 to the adjusted in a clockwise direction about shaft 51 as a temporarily fixed axis. Movement of link 58 to the right has the effect as previously described of adjusting one pump to increase its discharge and of adjusting the other pump to decrease its discharge. This will cause one of the cylinders,such as I I, to be supplied with fluid at a greater rate than the other cy 'nders l2 and-accordingly platen 5 will move upwardly faster than platen 8. This differential movement will be reflected in differential mechanism 25 whose eccentric 5| will be immediately angularly adjusted to shift rod 53 to the left and thereby also to swing levers 54 to the left which will cause arms 59 and 58 to pivot about the stationary lower end of arm 59 which will be held against movement by link I09 and worm gear I82 which are supported in a fixed position. Hence, arm 58 in swinging to the left will pull link 50 to the left thereby adjusting the pumps toward equal discharge positions. The eccentric 5| will continue to reflect any differential movement between the platens 5 and 8 until the pumps are on equal discharge and thereafter the arms and end platens will move up together at the same rate and thereby maintain the newly selected axial relation of the rams. In. this condition the eccentric has acquired a new normal fixed angular position. If it is desired to adjust the beam 4 to the opposite angularity, then gears I02 are adjusted to rotate arm two platens the right so as to return arm mal position, the arm 59 being pivotally held at.

58 in a counterclockwise direction tending to shorten the distance between shaft 51 and 83 by shaft 83 being pulled over to the left. This will immediately unbalance the discharge rela tlon between the two pumps and cause any increased supply offiuid to one set of the main cylinders for lifting say end platen 6 and a decreased supp to the other cylinders. This will result in a differential movement between the which will again be reflected in difto swing the first set of levers 54 to 58 toward its herferential 25 its lower'end by link I88 and gears I02. The differential movement which is reflected through the differential mechanism 26 ceases when the pumps have been adjusted back to their equal discharge positions.

The angular adjustment above described can be effected while the press is standing still or while it is in operation. If both pumps are on full stroke position and should any adjusting effect take place so as to further increase the discharge from one of the pumps the controlling force for effecting this discharge will merely compress spring 89, Fig. 6, it being understood that the pump under question cannot be adjusted to a greater discharge because it is already assumed to be at maximum discharge. During this attempted adjustment of the first pump the second pump will be adjusted to a decreased rate of discharge until the platens 5. and 6 are brought to their desired angular adjustment and are moving at the same rate. I

From the foregoing disclosure it is seen that I have provided two pumps adapted to be oppositely adjusted from equal discharge positions in response to relative movement or relative axial displacement between the two sets of rams and that the pumps are restored to equal discharge positions when the two rams are restored to their original relative axial relation at which time theywill have identical rates of movement. By opposite adjustment of the pumps is meant an increased discharge of one pump and a decreased discharge from the other pump. It is also seen that the means I02, etc. for angularly adjusting the beam 4 is broadly an arrangement for shortening or lengthening the distances between the differential mechanism 25 and shaft 88 and that the differential mechanism comprises a means for automatically restoring the normal distance between these two points when the desired angular adjustment of the beam has been accomplished. Thus it is seen that the differential mechanism constitutes means responsive to relative movement between the two sets of rams and the various links and lever are means operated by the responsive means for adjusting the pumps or supply of power fluid to establish identical movement of the two sets of rams. If the angular adjusting mechanism I02 were omitted the links 53 would be connected directly to arm 5|. However, the arrangement of links and levers of the angular adjusting mechanism I82 as well as of the pressing or manual control lever 88 is such that none of these devices interfere with the other or restricts their respective actions in any way thus being conducive to a high degree of flexibility of operation but without sacrificing sensitivity, accuracy or responsiveness. The bending beam 4 may be adjusted to any desired angularity with a high degree of nicety regardless of whether the beam is stationary or moving, or whether it is in engagement with a plate undergoing bending.

It will of course be understood that various changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention a set forth in the appended claims.

I claim:

1. A control system for a plurality of independently movable power operated mechanisms reciprocated bya power medium and having means responsive to variations from 'apredetermined relation of the power operated mechanisms relative to each other during movement thereof comprising, in combination, a plurality of levers adapted to' increase the supply of operating medium to one of said power mechanisms and to decrease the supply to the other or vice versa depending upon the direction of said variation, means for transmitting motion from said responsive means to saidlevers to operate the same'in accordance with the variations, and means for adjusting said levers so as to establish an initial predetermined relation between said power operated mechanisms including an arm operatively connected to said motion transmitting means and so disposed that one endv of the arm may normally latter in accordance with depending upon the direction of said variation, means for transmitting motion from said responsive means to said control means to operate the the variations, and means for adjusting said control means so as to establish an initial predetermined relation between said power operated mechanlsms including an element operatively connected tosaid motion transmitting means so as tomove therewith and having a portion that normallyv remains in a fixed position during such movement and means for adjusting the location of that portion of said element that remains in a normally fixed posil tion whereby the predetermined relation between remain stationary while the other end of the arm moves with the transmitting means and means for adjusting the location of the normally stationary end of said arm whereby the predetermined relation between said power operated mechanisms is adapted to be varied.

2. A control system for a plurality of independently movable power operated mechanisms reciprocated by a power medium and havin means responsive to variations from a predetermined re lation of the power operated mechanisms relative to each other during movement thereof comprising, in combination, a plurality of control 4 means adapted to increase the supply of power medium to one of said power mechanisms and to decrease the supply to the other or vice versa means being connected to said said power operated mechanisms is adapted to be varied.

3. The combination set forth in claim 2 further characterized in that said element of the adjusting means comprises an arm mounted upon a fixed axis; gears for adjusting said arm about said axis, and the operative connection between the' element and said motion transmitting means includes an arm connected to said motion transmitting means and a link pivotally connecting said arms together wherebysaid link and the ends of said arms to which said link is connected remain normally stationary while the remainder of the arm which is connected to the motion transmitting means moves therewith.

4. The combination set forth in claim 1 further characterized by the provision of a frame pivotally supported at one end abouta normally fixed axis and whose other end is adapted to swing about said axis, the plurality of levers being mounted upon the swinging end of said frame to said motion transmitting frame so as to move therewith, and

swing the same and also swing said plurality of levers thereby to increase the supply to one of said power mechanisms and decrease the supply to the other or vice versa, depending upon the direction in which said frame is swung.

PAUL C. COLLINS. 

